A crankshaft of an internal combustion engine is supported by, for example, a bulkhead formed on a cylinder block and a bearing cap fixed to the bulkhead.
JP 93-062216U, published in 1991 by the Japan Patent Office, proposes a bearing structure in which a bearing cap is fitted into a recessed part formed on a bulkhead and fixed to the bulkhead with bolts. In this bearing structure, chamfers are formed at both ends of the bearing cap in a transverse direction of a crankshaft and grooves are formed at both corners of the recessed part to oppose the chamfers, so that the bearing cap does not cause stress concentration at both ends of the recessed part of the bulkhead during operation of the internal combustion engine.